The present invention relates to a closed motor-driven compressor that is connected to a refrigerating cycle provided in an electric refrigerator or the like.
FIG. 4 depicts a conventional closed motor-driven compressor as disclosed in Japanese Laid-Open Patent Publication (unexamined) No. 8-284826. The compressor shown therein includes a closed vessel 1 containing a lubricating oil 2 collected in a bottom portion thereof. The closed vessel 1 accommodates a compression section 3 and a motor section 4, both elastically supported therein. The compression section 3 is driven by the motor section 4 via a crankshaft 5, which has a lower end 6 submerged in the lubricating oil 2 and an upper end 7. The crankshaft 5 is rotatably supported by a block 8 having a cylinder 9 integrally formed therewith. The cylinder 9 has generally flat shoulder portions 10 formed on respective sides thereof. The block 8 is rigidly secured to the motor section 4 via two legs 11 and has a rib 12 integrally formed therewith. A cylinder head 13 for covering an open end of the cylinder 9 is secured to the rib 12, and a suction muffler 14 is disposed below the rib 12.
The conventional closed motor-driven compressor of the above-described construction operates as follows.
When the operation of the compressor is started, the crankshaft 5 is rotated by the motor section 4, and the lubricating oil 2 sucked up from the lower end 6 of the crankshaft 5 spouts out from the upper end 7 of the crankshaft 5 and is then sprinkled on the closed vessel 1, cylinder 9, rib 12 and the like. The resultant drops of oil flow towards the generally flat shoulder portions 10. When the oil collected on the generally flat shoulder portions 10 overflows, it flows down to the bottom portion of the closed vessel 1 over the peripheral edges of the generally flat shoulder portions 10.
In the above-described construction, however, the oil collected on the generally flat shoulder portions 10 drops on and flows over the suction muffler 14. Accordingly, the internal temperature of the suction muffler 14 increases and, hence, the temperature of a suction gas also increases, resulting in a reduction in compressor efficiency. In the case where the oil collected on the generally flat shoulder portions drops directly on the bottom portion of the closed vessel 1, noise is generated at the surface of oil collected therein.
U.S. Pat. No. 5,322,419 which forms the closest prior art from which the present invention starts discloses a freon operated compressor for domestic refrigerators having an electric motor which drives through a cramshaft a piston sliding inside a cylinder block. A system of valves is provided for suction and delivery of the working fluid. That known compressor comprises furthermore a hollow body with a suction port in coaxial relation with a pipe, opposite which a tripple pole terminal is arranged through which electrical power is applied. Finally, a pump is provided with an outward cylindrical member and an ogival member with inner longitudinal blades and outward radial blades.
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide an improved closed motor-driven compressor wherein the oil collected on the generally flat shoulder portions is guided to the bottom portion of the closed vessel, while preventing the oil from dropping on and flowing over the suction muffler, and also preventing the oil from dropping directly on the bottom portion of the closed vessel.
In accomplishing the above and other objectives, the closed motor-driven compressor according to the present invention includes a closed vessel containing a lubricating oil collected in a bottom portion thereof, a compression section accommodated in the closed vessel, and a motor section accommodated in the dosed vessel for driving the compression section. The compression section includes a crankshaft having a lower end submerged in the lubricating oil and an upper end, and a block for rotatably supporting the crankshaft. The block has a cylinder formed therewith and having an open end, and also has a rib formed therewith, a generally flat shoulder portion formed on one side of the cylinder, and a leg formed below the generally flat shoulder portion and secured to the motor section. A cylinder head is secured to the rib for covering the open end of the cylinder, and a suction muffler is disposed below the rib. An oil guide is formed with the block for guiding to the bottom portion of the closed vessel a lubricating oil that is sucked up from the lower end of the crankshaft, caused to spout out from the upper end of the crankshaft, and collected on the generally flat shoulder portion.
Said oil guide includes an oil retainer wall formed on one side of the rib and connected to both the rib and the generally flat shoulder portion.
Advantageously, the oil guide also includes an oil groove extending downwardly from the generally flat shoulder portion.
By this construction,the oil guide prevents the oil from dropping on and flowing over the suction muffler, and also prevents the oil from dropping directly on the bottom portion of the closed vessel.